The motion of the piston rod of the conventional oil pressure cylinder is regulated by the oil pressure power supply system which is composed of the oil pressure pump and the oil container and is therefore relatively large in size. It is therefore readily conceivable that the conventional oil pressure cylinder is not cost-effective, and that the conventional oil pressure cylinder takes up too much of the space of a machine tool to which the conventional oil pressure cylinder is attached, and further that the conventional oil pressure cylinder can not be fitted into a compact machine tool.